Warning signs and symptoms of a heart attack

Around 100,000 people in the UK are admitted into hospital due to a heart attack, also known as a myocardial infarction, every year. It occurs when the blood supply to your heart suddenly stops due to a blockage in the blood vessels that supply it. 

A heart attack is a medical emergency. If you notice someone having a heart attack, you should call 999 immediately. 

What causes a heart attack?

Your heart pumps blood throughout your body but like any other tissue, it also needs its own blood supply. Oxygen-rich blood is delivered to your heart by blood vessels called coronary arteries. A heart attack occurs when one of these coronary arteries is suddenly blocked. 

In most cases, the blockage is caused by the build-up of cholesterol in your coronary arteries called atheroma or plaques. This leads to coronary artery disease, also known as coronary heart disease, which causes your coronary arteries to narrow. This reduces the amount of oxygen-rich blood that can reach your heart. In some cases, narrowing alone (ie a partial blockage) is enough to cause a heart attack. 

If part of the atheroma breaks off (ruptures), it can trigger a blood clot to form in the coronary artery. This can completely block the artery, causing a heart attack. If the blood clot travels elsewhere in your body, it can block a different blood vessel, such as in your brain, where it causes a stroke. 

A heart attack can lead to cardiac arrest, where the electrical signals of the heart are disturbed, which causes the heart to stop beating. 

Who is at risk of a heart attack?

Heart attacks affect both men and women. Of the 100,000 people admitted to hospital every year in the UK with a heart attack, 30,000 are women. 

The biggest risk factor for heart attack is coronary heart disease. 

Your risk of coronary heart disease and consequently a heart attack is higher if you have a family history of coronary heart disease, if you have high cholesterol, high blood pressure, diabetes or prediabetes, are stressed, overweight or obese, smoke, lead a sedentary lifestyle, drink too much alcohol or follow a diet high in saturated and trans fats. 

Sleep apnoea also increases your risk of heart attack. It causes you to temporarily stop breathing when you're sleeping and every time this happens, your body responds by increasing your adrenaline levels. Over time, this can lead to high blood pressure and heart problems. 

Angina and heart attacks

Angina refers to chest pain caused by reduced blood supply to your heart, usually due to narrowing of your coronary arteries. This is a warning sign that you are at risk of having a heart attack or stroke. 

Heart attack symptoms

The most common symptom is sudden chest pain that doesn’t go away. This may feel like a heaviness, tightness, squeezing or pressure across your chest. Although chest pain is usually severe, it can sometimes be milder and feel like indigestion. 

Your chest pain may spread elsewhere, often to the arms (sometimes only the left arm), back, jaw, neck and tummy. 

Other heart attack symptoms include coughing, dizziness or lightheadedness, nausea, breathlessness, sweating, vomiting and wheezing. You may also feel as if you are having a panic attack ie you suddenly feel overwhelmed by anxiety. 

You may not experience all of these symptoms and their severity can vary. Both men and women can develop these symptoms. However, women are more likely to develop symptoms of back or jaw pain, breathlessness, nausea and vomiting, in addition to the chest pain that most people experience. 

If you’re concerned that you’re having a heart attack, you or whoever is with you should call 999 immediately. Do not attempt to drive yourself to the hospital — this will put you and others at risk of injury. 

How to help

If someone is having a heart attack, after calling 999, stay with them, ask them to sit down and rest, and try to remain calm. If they are not allergic to aspirin, you can give them a single tablet (300 mg aspirin) to chew on.

If you change location or their symptoms worsen, you should call 999 again to inform the emergency services. 

Diagnosing a heart attack

If a heart attack is suspected, soon after arriving at the hospital you will have an electrocardiogram (ECG) to measure the electrical activity of your heart. This involves placing four flat discs (electrodes) attached to wires onto your arms, chest and legs. This will detect your heart’s electrical activity and send the measurements to the ECG machine.

These results will allow your doctor to diagnose whether you’re having a heart attack. Based on a particular part of the measurements taken called the ST segment, your doctor can also diagnose what type of heart attack you’re having. 

There are two types of heart attack: ST segment elevation myocardial infarction (STEMI) and non-ST segment elevation myocardial infarction (NSTEMI). STEMI is more serious than NSTEMI as it causes more damage to the heart. NSTEMI can progress to STEMI if it is not treated. 

Treating a heart attack

Treatment for a heart attack depends on whether it is a STEMI or NSTEMI.

STEMI treatment unblocks the blocked coronary artery. Depending on when your symptoms started, this may involve taking medication to break down the blood clot blocking your coronary artery or having a minimally invasive surgery called a primary percutaneous coronary intervention (PCI).

If your symptoms started more than 12 hours ago and have improved, your treatment may instead involve having a coronary artery bypass surgery. This is where a blood vessel from another part of your body is used to reroute the blood passing through your coronary artery to ‘bypass’ the blockage. 

You will also be given medication to prevent more blood clots (eg aspirin). 

NSTEMI treatment usually involves taking medication to prevent blood clots and in some cases, surgical treatment eg a coronary angioplasty or coronary artery bypass. 

Recovering from a heart attack

Recovering from a heart attack takes several months and focuses on restoring your fitness so you can return to your usual activities (cardiac rehabilitation), as well as reducing your risk of future heart attacks. 

This involves building up an exercise routine and making lifestyle and dietary changes, specifically following a healthy diet, low in salty, fatty, sugary and highly processed foods, and high in fresh fruits and vegetables, fibre, whole grains and lean protein.  

You will also be prescribed medication to reduce your risk of future heart attacks. This usually involves taking medication to prevent blood clots immediately after your heart attack and for up to 12 months afterwards. 

You may also need to take angiotensin-converting enzyme (ACE) inhibitors to help reduce your blood pressure, beta blockers to reduce the strain on your heart and statins to reduce your blood cholesterol levels. You may need to take some or all of these medications for the rest of your life.  

Heart attack complications

A heart attack can lead to cardiac arrest, where the electrical activity of your heart is disrupted, causing it to stop beating.

In the first few days after a heart attack, if damage to your heart is severe, you may develop cardiogenic shock, where your heart can’t pump enough blood to the rest of your body. This needs immediate treatment with medication and you may later need surgery. 

Damage to your heart tissue after a heart attack can also cause an abnormal heartbeat (arrhythmia) or in more severe cases, heart failure, which needs treatment with medication and in some cases, surgery. 

Reducing your risk of a heart attack

To reduce your risk of a heart attack, it is important to maintain a healthy blood pressure and blood cholesterol level. 

This involves quitting smoking, avoiding drinking more than 14 units of alcohol per week, exercising regularly and following a healthy, balanced diet, ensuring you avoid foods high in saturated and trans fats as much as possible.